The common housefly, Musca domestica, is present at one time or another in nearly every habitation in the world. Exposure to manure piles, sewage, garbage, sputum, animal carcasses, food of all kinds, and to the lips, eyes, and nursing bottles of sleeping children is xe2x80x9call in the day""s workxe2x80x9d for a housefly. In addition to its disagreeable presence and habits, the housefly has long been suspected as a vector of many human and animal diseases. For example, in India and North Africa the housefly is a major factor in the spread of the trachoma virus and its associated Haemophilus bacterium that afflicts 80 million people and is a major cause of blindness (Metcalf and Metcalf, 1993). If uncontrolled, houseflies in Europe compromise animal production and the housefly control market in this area alone is $10-20 MM. Residual spraying with organochlorine, organophosphorus, carbamate, and pyrethroid insecticides on residential or animal-rearing structures has increasingly been of public concern and rapidly results in the selection of cross-resistant fly strains.
A safe, fast-acting, and resistance-reducing or preventing housefly control method is needed. Denmark and the United Kingdom have been pursuing various control mechanisms combined with baiting strategies as the primary means of controlling houseflies for livestock producers. A formulation containing a sugar base, an attractant, and a non-repellant toxicant has been a bait standard.
The fermentation product identified in U.S. Pat. No. 5,362,634 as A83543 is a family of related compounds produced by Saccharopolyspora spinosa. These compounds have been referred to as factors or components A, B, C, D, E, F, G, H, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, Y, and the like (also see published international patent application WO 93/09126 and WO 94/20518) and are hereinafter referred to as spinosyn A, B, C, and so on. Spinosyn compounds are environmentally friendly and have an appealing toxicological profile. The naturally produced spinosyn compounds consist of a 5,6,5-tricylic ring system, fused to a 12-membered macrocyclic lactone, a neutral sugar (rhamnose), and an amino sugar (forosamine) (see Kirst et al. (1991)). Natural spinosyn compounds may be produced via fermentation from cultures deposited as NRRL 18719, 18537, 18538, 18539, 18743, 18395, and 18823 of the stock culture collection of the Midwest Area Northern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, 1815 North University Street, Peoria, Ill. 61604. Spinosyn compounds are also disclosed in U.S. Pat. Nos. 5,496,931, 5,670,364, 5,591,606, 5,571,901, 5,202,242, 5,767,253, 5,840,861, 5,670,486, and 5,631,155. The spinosyn compounds are useful for the control of arachnids, nematodes, and insects, in particular Lepidoptera and Diptera species.
Spinosyn A and spinosyn D are two spinosyns that are particularly active insecticides. A product comprised mainly of these two spinosyns (approximately 85% spinosyn A and approximately 15% spinosyn D) is produced by Dow AgroSciences (Indianapolis, Ind.) known as spinosad. Spinosad is an active ingredient of several insecticidal formulations available commercially from Dow AgroSciences, including the TRACER, SUCCESS, SPINTOR, and CONSERVE insect control products. For example, the TRACER product is comprised of about 44% to about 48% spinosad (w/v), or about 4 pounds of spinosad per gallon.
It has been reported that spinosad is highly toxic to houseflies under experimental conditions in which spinosad was applied to the thoracic notum of the flies (Scott, 1998). King and Hennessey (1996) described the use of an insecticidal composition comprising spinosad in a sugar and yeast hydrolysate mixture to control Caribbean fruit flies. Adxc3xa1n et al. (1996) disclosed that adult C. capitata were susceptible to spinosad through residual contact with spinosad dried on glass plates and via ingestion in drinking water.
Typically, a bait station device is employed to deliver an insecticide for the control of insects in a household or commercial environment when minimal exposure to persons or other animals is desired. A number of bait station devices containing insecticide have been described in the art. For example, U.S. Pat. No. 5,501,033 discloses a two-stage liquid bait-toxicant delivery device having an upper and lower reservoir which allows for sequential delivery of two separate liquids to an absorbent feeding pad, e.g., delivery of a bait-only formulation first, followed by a bait-toxicant formulation once the bait-only formulation is expended. Liquid is delivered from the lower reservoir to the absorbent pad via a wicking system. The device is designed to xe2x80x9ctrainxe2x80x9d flying insects such as wasps to feed at the device using the bait-only formulation before they are exposed to the bait-toxicant formulation.
U.S. Pat. No. 4,310,985 (the ""985 patent) discloses a device for killing arthropods that uses an absorbent material onto which an insecticide is applied and allowed to dry. When the device is ready to be used, one portion of the insecticide-coated absorbent material and/or a wicking material is placed into a solution such as water. Arthropods contacting the moistened absorbent material are killed by the insecticide.
U.S. Pat. No. 4,908,977 discloses a device similar to that in the ""985 patent mentioned above. The device, which can be used in a xe2x80x9cwetxe2x80x9d or xe2x80x9cdryxe2x80x9d form, comprises a target area containing an insecticide. In the wet form, fluid in a reservoir is wicked to the target area so that the target area remains moist while in use.
U.S. Pat. No. 1,916,982 discloses a device that uses an absorbent pad impregnated with a fly poison. One portion of the pad is in contact with a water-filled reservoir to maintain moisture throughout the pad. The moistened pad draws from an adjacent cavity containing a sugar and fly poison mixture.
Various insecticidal baits and attractants have also been described in the art. For example, U.S. Pat. No. 4,351,834 discloses an insecticidal bait for the control of houseflies that comprises an insecticide plus sugar and milk mixed in sugar water and absorbed onto absorbent cotton material. Houseflies were allowed to feed on the material to determine the activity of the composition.
U.S. Pat. No. 4,886,899 (the ""899 patent) discloses housefly chemosterilants provided in a fly feed mixture comprising, for example, dried milk, sugar, powdered eggs, malt, molasses, and yeast. The ""899 patent also discloses drying a solution of the chemosterilant/feed mixture to prepare a dry feed which is made available to the flies in a bait dispenser.
U.S. Pat. No. 5,567,429 discloses pest controlling compositions that include bait and attracting substances including flour, corn powder, starches, sugars, glycerin, and food flavors such as milk flavor.
U.S. Pat. No. 5,972,330 discloses pesticidal baits that comprise insect attractants and baiting substances such as cereal powders, starches, and sugars.
As can be seen from the above, there have been numerous efforts to control flying insects, however, many of these use insecticides that do not have a particularly appealing toxicological profile or have not been particularly effective. Thus, there remains a need in the art for simple but effective bait devices for controlling houseflies. An effective bait device should use a long lasting and cost-efficient attractant to attract flies to the bait. The insecticide incorporated in the bait device should be one that can be used at a very low concentration in the bait in order to obtain an efficacy which is equivalent or superior to current commercial bait standards. The present invention advantageously provides a housefly bait station which is safe, highly effective, stable during storage, and transportation, affordable to customers, and easy to use (users need to add only water to the station before use). It has been discovered that incorporating spinosad as the insecticide, in conjunction with a volatile fly attractant and feeding stimulant has numerous advantages over conventional broadcast applications of granular baits for housefly control. The bait station devices of the present invention greatly reduce the amount of active ingredient used and exert less impact on non-target organisms.
The subject invention concerns compositions and devices for controlling houseflies. The compositions of the present invention comprise the insecticide spinosad. The devices of the invention are directed to a housefly bait device that includes a means for providing bait materials comprising a housefly attractant, a feeding stimulant, and spinosad in an environment where control of houseflies is required. The device is inexpensive to construct, convenient to transport and store, easy, and safe to apply and clean up, and is highly effective in the control of houseflies. In a preferred embodiment, the device of the invention uses xe2x80x9cbarsxe2x80x9d that are prepared by coating bait materials onto a portion of an absorbent material. In an exemplified embodiment, the absorbent material is a cotton roll.
In one embodiment, a commercially available spinosad formulation is used as the insecticide. In an alternative embodiment, a spray dried waste broth containing spinosad resulting from spinosad production is used as the toxin. When used to control houseflies, however, the spinosad formulation can be wetted to significantly increase its attractiveness and knockdown power. In one embodiment, the spinosad used in the formulation is obtained from the TRACER insect control product.
A bait material bar of the present invention containing adult fly food, yeast, cornmeal, and 0.1% spinosad (dry weight) provided more effective control of houseflies than did a commercial standard (1% methomyl) within eight (8) hours. The subject bar continued to outperform the standard at 24 and 32 hours after exposure.